1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) panel. More particularly, the present invention relates to an LCD panel having a polymer layer for assisting alignment.
2. Description of Related Art
Fabrication of an LCD includes fabricating an LCD panel and assembling a liquid crystal module (LCM). The fabrication of the LCD panel is mainly to package a liquid crystal layer between a color filter substrate and a pixel array substrate. To arrange liquid crystal molecules in a specific inclination angle to achieve a wide viewing angle display effect, an alignment structure is generally applied to the LCD panel.
The commonly used alignment structure includes alignment protrusions and alignment slits disposed on an electrode. The liquid crystal molecules in the liquid crystal layer can be arranged in multi-domain alignment by applying the alignment protrusions and the alignments slits, so as to achieve the wide viewing angle display effect. However, the liquid crystal molecules located around the alignment protrusions and the alignment slits generally represent in an ambiguous disclination, which may lead to dark stripes in the bright-state or light leakage in the dark-state so that a display contrast of the LCD panel is decreased. Therefore, a polymer stablilized alignment (PSA) technique is brought forward.
According to the PSA technique, monomers are first doped into the liquid crystal layer located between the color filter substrate and the pixel array substrate, and a specific voltage is applied to the liquid crystal layer. Meanwhile, the liquid crystal layer is irradiated by ultra violet (UV) light under such specific voltage. Now, the monomers are polymerised and cured to form polymer layers at two sides of the liquid crystal layer. The molecules of the polymer layer have a specific configuration, which avails alignment of the liquid crystal molecules. The arrangement of the liquid crystal molecules can be more stable according to the PSA technique, and applying of the alignment protrusions is unnecessary, so that the LCD panel is not liable to have the problems of dark stripes in the bright-state or light leakage in the dark-state, and transmissivity of the LCD panel is improved.
However, when the monomers are irradiated by the UV light to form the polymer layer, the monomers have to absorb enough energy for polymerization. Therefore, during the PSA process, an exposure time has to be long enough for performing the polymerization. In other words, productivity is influenced due to the relatively long exposure time of the PSA process.
In detail, if the exposure time is inadequate, curing of the monomers is incomplete, so that alignment of the liquid crystal molecules cannot be effectively assisted. Therefore, a response time and performance of the LCD panel are restrained. If the exposure time is suitably prolonged, the response time and performance of the liquid crystal molecules can be meliorated. However, on the other hand, the productivity of the LCD panel is restrained and the contrast of the LCD panel is decreased. Therefore, the PSA technique requires to be further improved.